Object display device

Abstract

The present invention provides a target display device capable of displaying the bow direction and direction of movement of a target that does not transmit its bow direction. [Solution] The system includes an AIS receiver 2 that acquires AIS data including the positions of targets in the vicinity of the vessel, and a display control unit 4 that displays symbols representing targets on a display unit 3 corresponding to the positions of the targets based on the AIS data. The display control unit 4 displays the symbols on the display unit 3 with the orientation of the target facing the bow direction if the AIS data includes the bow direction of the target, and calculates the direction of movement of the target based on the history of the target's position, and displays the symbols on the display unit 3 with the orientation of the target facing the direction of movement if the AIS data does not include the bow direction of the target.

Description

Technical Field

[0001] This invention relates to a target display device for displaying targets at sea.

Background Art

[0002] Conventionally, a ship automatic identification device (AIS device, Automatic Identification System) that transmits and receives ship information such as the name, position, heading (course), and speed of ships to each other and displays the ship information of other ships is known (for example, see Patent Document 1, etc.). In this ship automatic identification device, there is one that can grasp the heading of other ships at a glance by aligning the direction of an arrow-shaped symbol representing other ships with its heading.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in recent years, an AIS buoy that transmits identification information, position, etc. of a target to ships, etc. is attached to a fishing net to monitor the position of the fishing net. Therefore, the position of the AIS buoy is also displayed on the ship automatic identification device of the ship.

[0005] However, since the information transmitted by the AIS buoy often does not include the heading (course, Heading information) of the AIS buoy, on the ship automatic identification device of the ship, all the symbols representing the AIS buoy are displayed facing the same direction. For this reason, the heading and moving direction of the AIS buoy and the fishing net are unknown, which may hinder safe navigation.

[0006] Therefore, the present invention aims to provide a target display device capable of displaying the bow direction and direction of movement of a target that does not transmit its bow direction. [Means for solving the problem]

[0007] To achieve the above objective, the invention described in claim 1 is a target display device comprising: a data acquisition unit that acquires target data including the positions of targets present around the ship; and a display control unit that displays a symbol representing the target on a display unit corresponding to the position of the target based on the target data, wherein the display control unit displays the symbol on the display unit with the orientation of the symbol in the direction of the ship's bow if the target data includes the bow direction of the target; and calculates the direction of movement of the target based on the history of the target's position and displays the symbol on the display unit with the orientation of the symbol in the direction of movement if the target data does not include the bow direction of the target.

[0008] The invention described in claim 2 is characterized in that, in the target display device described in claim 1, if the target data does not include the bow direction of the target but includes the relative position of the target, the display control unit displays the symbol on the display unit with the orientation of the symbol relative to the relative position. [Effects of the Invention]

[0009] According to the invention described in claim 1, if the bow direction of the target can be obtained, the symbol representing the target is displayed with its orientation facing the bow direction. On the other hand, if the bow direction of the target cannot be obtained, the direction of movement of the target is calculated based on the position history and trajectory of the target, and the symbol is displayed. The symbol is displayed with the direction of movement as the orientation of the object. In this way, even if the target does not transmit its bow direction, the direction of the target's movement can be displayed as the bow direction. For example, if the target is an AIS buoy attached to a fishing net, it is possible to know at a glance which direction the AIS buoy, and thus the fishing net, is drifting, enabling safe navigation.

[0010] According to the invention described in claim 2, for a target that does not transmit its bow direction but transmits its relative position, the symbol is displayed with its orientation set to the relative position. In this way, even for a target that does not transmit its bow direction, its relative position can be displayed as the bow direction. Moreover, because the symbol's orientation is displayed with the relative position received from the target, it is possible to display the correct target orientation in real time, rather than the direction of movement based on the target's position history. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic block diagram showing a target display device according to an embodiment of the present invention. [Figure 2] This diagram shows the processing flow by the display control unit of the target display device shown in Figure 1. [Figure 3] Figure (a) shows the conventional symbol representation when heading information is unavailable, Figure (b) shows the past and present positions of the target, and Figure (c) shows the symbol representation with the direction of movement as the bow direction. [Figure 4] This figure shows the symbol display by the display control unit of the target display device shown in Figure 1. [Figure 5] Figure (a) shows the display state including the AIS buoy symbol in a conventional target display device, and Figure (b) shows the display state including the AIS buoy symbol in the target display device of Figure 1. [Modes for carrying out the invention]

[0012] The present invention will be described below based on the illustrated embodiments.

[0013] Figure 1 is a schematic block diagram showing a target display device 1 according to an embodiment of the present invention. This target display device 1 is a device for displaying targets at sea, and its basic configuration is equivalent to known and existing ship radar devices and electronic chart display devices (ECDIS devices) equipped with AIS, so the differences in configuration will be mainly described below.

[0014] In essence, the system comprises an AIS receiver (data acquisition unit) 2 that receives and acquires AIS data (target data) including the positions of targets (including other ships and AIS buoys) around the vessel, and a display control unit 4 that displays symbols representing targets on a display unit 3, corresponding to the target's position, based on the AIS data. When the AIS receiver 2 receives AIS data (ship information) from another ship, including the ship's name, position, heading information, and speed, the display control unit 4 displays symbols representing the other ship at a predetermined position on the display unit 3 based on the AIS data. Here, the predetermined position is the position on the radar screen displayed on the display unit 3 that corresponds to the other ship's position. All received AIS data (data from other ships, AIS buoys, etc.) is stored sequentially in memory.

[0015] On the other hand, the GNSS receiver calculates the ship's position based on radio waves from the GNSS (Global Navigation Satellite System), the GNSS compass calculates the ship's heading, and the antenna emits radar around the ship to calculate the position and speed of targets (including those that do not transmit AIS data) based on the reflected waves from the targets. This information is then processed by the display control unit 4 and displayed on the display unit 3.

[0016] In this basic configuration, the display control unit 4 identifies the orientation of the symbol representing the target based on the information contained in the AIS data and displays it on the display unit 3.

[0017] That is, as shown in FIG. 2, first, the AIS data (AIS signal) is analyzed (step S1). When the sentence of the AIS data contains valid Heading information (when it is "yes" in step S2), symbols are drawn according to this Heading information (step S3). That is, as shown in FIG. 4, the direction and orientation of the arrow-shaped or isosceles triangle-shaped symbol representing the target are displayed on the display unit 3 in accordance with the heading direction, which is the Heading information. That is, the symbol is displayed such that the direction in which the apex angle of the isosceles triangle-shaped symbol faces coincides with the heading direction. Here, since the AIS data from a predetermined large other ship usually contains Heading information, the symbol representing such an other ship is usually displayed facing the heading direction.

[0018] On the other hand, when the sentence of the AIS data does not contain valid Heading information (when it is "no" in step S2), but the sentence of the AIS data contains valid COG information (Course Over Ground, course over ground azimuth information) (when it is "yes" in step S4), symbols are drawn with the course over ground azimuth of this COG as the Heading information and the heading direction (step S5). That is, the direction and orientation of the isosceles triangle-shaped symbol are displayed on the display unit 3 in accordance with the course over ground azimuth of the COG.

[0019] Furthermore, when the sentence of the AIS data does not contain valid Heading information (when it is "no" in step S2) and the sentence of the AIS data does not contain valid COG information (when it is "no" in step S4), the moving direction of the target is calculated based on the history of the position of the target (past positions, trajectories) (step S6). That is, the starting trajectory in which the target has moved from the past position to the current position is calculated as the moving direction. At this time, as shown in FIG. 3(b), the moving direction may be calculated from only the current position and its immediately previous past position, or the moving direction may be calculated from a plurality of past positions and the current position.

[0020] Next, the symbol is drawn with the calculated moving direction as the bow direction and the Heading direction (step S7). That is, as shown in Fig. 3(c), the direction and orientation of the isosceles triangle-shaped symbol are displayed on the display unit 3 in accordance with the calculated moving direction. If such a moving direction is not calculated, as in the prior art, regardless of the actual orientation and bow direction of the target, as shown in Fig. 3(a), all symbols are displayed facing the 0-degree direction with respect to the north reference. Here, since the AIS data from the AIS buoy generally does not include Heading information or COG information, the symbol representing such an AIS buoy is displayed facing the moving direction.

[0021] According to the target display device 1 with such a configuration, when the Heading information and bow direction of the target can be obtained, the symbol representing the target is displayed with the direction of the symbol being the bow direction. Therefore, for a target that transmits Heading information and bow direction, the symbol can be displayed facing the correct bow direction. On the other hand, when the Heading information, bow direction, COG information, and relative bearing of the target cannot be obtained, the moving direction of the target is calculated based on the history and trajectory of the target's position, and the symbol is displayed with the direction of the symbol being the moving direction.

[0022] That is, conventionally, when the Heading information, bow direction, COG information, and relative bearing of the target cannot be obtained, for example, in the case of a plurality of AIS buoys attached to a fishing net, as shown in Fig. 5(a), all symbols are uniformly displayed facing north. Therefore, it is impossible to know and grasp in which direction the AIS buoy, that is, the fishing net, is being drifted, and it becomes difficult to navigate safely.

[0023] In contrast, in this target display device 1, even for a target that does not transmit Heading information, bow direction, COG information, and relative bearing, the moving direction of the target is displayed as the bow direction. For example, in the case of a plurality of AIS buoys attached to a fishing net, as shown in Fig. 5(b), all symbols are displayed facing the moving direction. Therefore, it is possible to immediately know in which direction the AIS buoy, that is, the fishing net, is being drifted, and also the direction of the tidal current (the dashed arrow in the figure) This makes it possible to predict these conditions and navigate safely.

[0024] Furthermore, for targets that do not transmit heading information but do transmit COG information and relative position, the symbol is displayed with its orientation relative to the relative position. In this way, even for targets that do not transmit heading information, the target's relative position can be displayed as the heading. Moreover, because the symbol's orientation is displayed with the relative position received from the target, it is possible to display the correct target orientation in real time, rather than the direction of movement based on the target's position history.

[0025] Although embodiments of this invention have been described above, the specific configuration is not limited to the embodiments described above, and any design changes, etc., that do not depart from the gist of this invention are also included. For example, in the embodiments described above, the case in which the target data is AIS data was described, but the target data may be other than AIS data. Also, although the case in which the symbol representing the target is an isosceles triangle was described, other symbol shapes are also acceptable as long as the direction and orientation are known. [Explanation of Symbols]

[0026] 1 Target display device 2. AIS receiver (data acquisition unit) 3 Display section 4 Display Control Unit

Claims

1. A data acquisition unit that acquires target data including the positions of targets present around the ship, A display control unit that displays a symbol representing the target on a display unit corresponding to the position of the target, based on the target data, The display control unit comprises the following: If the target data includes the bow direction of the target, it displays the symbol on the display unit with the orientation of the symbol facing the bow direction; if the target data does not include the bow direction of the target, it calculates the direction of movement of the target based on the position history of the target and displays the symbol on the display unit with the orientation of the symbol facing the direction of movement. A target display device characterized by the following features.

2. If the target data does not include the bow direction of the target but does include the relative position of the target, the display control unit displays the symbol in the direction of the relative position on the display unit. The target display device according to feature 1.

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